Title: Densities of Floor-Dwelling Frogs and Lizards in Lowland Forests of Southeast Asia and Central America
Abstract: Two large samples of amphibians and reptiles from lowland primary rain forests in Borneo come from communities that appear to have densities similar to that of a Bornean community previously reported (Lloyd et al. 1968). To this group may be added a much smaller sample from a primary rain forest in peninsular Malaysia. Densities of nonriparian terrestrial frogs and lizards in these Indo-Malayan communities are about an order of magnitude smaller than those reported from lowland forests in Central America (Scott 1976). Indo-Malayan forests are peculiar among rain forests because of supraannual synchronized mast fruiting of dipterocarp trees that dominate them (Wood 1956; Ashton 1969). I suggest that this habit reduces the number of seed-eating insects and associated arthropod predators on the floor of these forests, thereby reducing the food supply of floor-dwelling frogs and lizards and acting to limit the populations of these animals below levels achieved in neotropical forests. Large samples of frogs and lizards obtained in two strongly seasonal forests in northeastern Thailand show that combined frog-plus-lizard densities in these two communities are very close to that measured in Borneo. Although both Thai forests are also dominated by dipterocarp species of trees, it is less clear that their seed production acts as a limiting factor. There is, however, one brief reference to mast fruiting in seasonal dipterocarp forests of Thailand. Both Thai communities differ from the Indo-Malayan ones in having much lower densities of frogs and much higher densities of lizards. If the combined density of these animals is limited by food supply in the Thai communities, reduction in the populations of frogs, which are strongly affected by a harsh seasonal climate, should lead to a counterbalancing increase in the numbers of terrestrial lizards. Terrestrial frogs in two disturbed forests in peninsular Malaysia seem to be three to four times more numerous than in Bornean and Malayan primary rain forests. This difference may reflect the seasonal limitation of those two samples, the abundance of species that might be called commensals of man, or some other unknown factor.
Publication Year: 1980
Publication Date: 1980-06-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 80
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